Materials Data on CrGaFeSe4 by Materials Project

CrFeGaSe4 crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three CrFeGaSe4 sheets oriented in the (0, 0, 1) direction. Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with three equivalent FeSe4 tetrahedra, corners with three equivalent GaSe4 tetrahedra, and edges with six equivalent CrSe6 octahedra. All Cr–Se bond lengths are 2.58 Å. Fe2+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with three equivalent CrSe6 octahedra and corners with six equivalent FeSe4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are three shorter (2.41 Å) and one longer (2.46 Å) Fe–Se bond lengths. Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share corners with three equivalent CrSe6 octahedra and corners with six equivalent GaSe4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are one shorter (2.42 Å) and three longer (2.47 Å) Ga–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Ga3+ atoms. In the second Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three equivalent Fe2+ atoms. In the third Se2- site, Se2- is bonded to three equivalent Cr3+ and one Fe2+ atom to form distorted SeCr3Fe trigonal pyramids that share corners with nine SeCr3Fe trigonal pyramids and edges with three equivalent SeCr3Ga trigonal pyramids. In the fourth Se2- site, Se2- is bonded to three equivalent Cr3+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing SeCr3Ga trigonal pyramids.